Semiautomatic telephone system



April 7, 1925. 1,532,849

B. D. WILLIS SEMIAU'IOMATIC TELEPHONE SYSTEM Original Filed June 22. 1918 2 Sheets-Sheet. 1

a I- n April 7, 1925. 1,532,849

B. D. WILLIS SEMIAUTOMATIC TELEPHONE SYSTEM Orizifl l Filed Jung 22. 1918 -Sheet 2 if i Ju U IHUEUZUP Bernard [7 M1115 Patented Apr. 7, 1925. 1,532,849

SEMIAUTOMATIC TELEPHONE SYSTEM. Application flied June 22, 1915, Serial No. 241,355. Renewed September 18, 1922. Serial No. 589,017.

To all whom it may concem: to this trunk over the normals thereof and Be it known that I, BERNARD D. iVILLIs, may slam! the p p havefihown no a iti f th U i d St t f A i supervisory or other circu ts assoclated with and a resident of Oak Park, in the county 9 answerlng end of 7311.13 it f C k d St t f Illi i h i t d being understood that this end of the cord 60 certain new and useful Improvements in m y be arranged to comma? With m nual Semiautomatic Telephone Systems,of which 1111535 S essible to a utomatic h f ll i i a ifi ti switches in any known manner. lhe toll y invention l t i general t selectors E have access to toll connectors proved means for setting up connections besuch g- 2) In their res ective extween subscribers in a system in which part g I11 each Selector E t ere are a of the connection is established by means of number of (lead levels (ZOITBSPOQdmg t0 the an operator's cord circuit and part by the number of exchanges Into Which he toll use of so-called automatic switches. trunk is p i that if 2 15 dialed More specifically, my invention relates to ver this trunk l ne then the toll selector in improved circuits and apparatus whereby a h 5 5? W111 p to the Second level! tw0 way trunk line may b d between a Wind! is dead in all except the #2 exchange, main exchange and a plurality of branch ex- 50 that l operatlon 0f Switches 111 all changes for setting up connections from the except l 3 a g l be Ineffective nain exchange to any f aid branches and b0 EStflbllSll l CODHECIUOH. The (30l'll'l8Ctfrom any branch to the main exchange,- H h access In he usual manner to and to accomplish this result by the use of a (Tuned 11995 Such 3S 5h0Wn F B simplex operating circuit su erimposed upon The Called Subscribers B In each exchange the conductors of said trunk line whereby a y have access through the medium 0f call from the branch to the main exchange any Switches Such as 'y connectors 30 in another branch over the same trunk line hue extendlilg cans the n Ofilce without interference or annoyance to the as be p ned.

pulling party I Wlll now describe theoperation of the In order to accomplish this and other new System when a can received y h P 35 results I have connected the said trunk line atol and extended h gh he SWltches E levels, corre onding in number to the nummg a Signal from P5 canlng S11 Sqriber 00 granch exchanges These selecstarts the plug P lntO the answering jack are ll t d i lti l b th of the calling line and throws the l stening orator in the main exchange, and only that lfl connect 1191 hffad Set X h d selector which strikes a live level is efl'eccaning The canmg Subscrlber then tire to further extend the connection, while f the Operator of the the rest of the selectors are left standing on scl'lber number d the p P Inserts the d l l the calling plug P Into the ack J asso- The drawings, comprising Figs. 1 and 2, mated with one end of trunk line 10 and 11 show by means of the usual circuit diad ng to the anch exchanges. This ingrams a trunk line and sufficient apparatus sertion of the plug P into the ack J closes in the main exchange and in one of the a circuit from ground through springs 7 branch exchanges to enable the invention to and relay 8 to battery. Relay 8 upon enoe explained and understood. ergizing disconnects the windings of relay In Fig. 1 of the drawings 1 have shown a 9 from the trunk conductors 10 and 11 and ord circuit which has access to an interconnects said conductors to the tip and ring various branch exchanges, one of said y closed from battery through the impulse sclectors being shown at E. This toll line springs of calling device C. D., springs of is of the two way type, that is, a subscriber key K (now in operated position), key K,

in any of the branch exchanges has access key K windings of relay 14 in multiple, ll.

conductors 10 and 11 in multiple, windings 15 and 16 of the repeatin coil in multiple, springs 17, sprin s 18 an 19, and relay 20 to ground throug springs 21. At the same time that the circuit of relay 20 is thus closed a circuit is also closed for as many other line relays such as 20 as there are small exchanges, that is, there are a number of other relays similar to relay 29 connected to the extension conductors 22 and 23 in the same manner, so that when the trunk such as 10 and 11 is seized from the ma1n exchange, the line relays of a plurality of switches are ener simultaneously, each line rela such as 20 bein associa with a toll se ector exactly simi ar to the toll selector E (Fig. 1).

The calling device may now be operated to send a plurality of im ulses to line relay 20 corresponding to a digit of the called number. Relay 20, in response to this series of impulses, operates the vertical magnet 32 over a circuit extending from groun through springs 21, spnngs 25 and 26, springs 28, springs 29 and 30, relay 31, and

' 32 to battery. Relay 24 envertical magnet ergizes as soon as rela pulls up to close to place ground y 20 5 rings 29 and and tlirough springs 33 on the private nor-ma contact 34 and its multiples in the banks of outgoing switches, and be ng slow acting, remains in opera position while relay 20 is vibrating its armature. of magnet 32 steps the wipers 35-38 inclusive to the live or active level of the bank, in which are terminated trunk lines leading to connectors such as H. Relay 31 1S energized in series wlth magnet 32, and ing slow acting, remains energ1 urmg this series of impu and as soon as the oil normal springs 39 close a circuit is closed for the rotary interrupter relay 40 from ground through springs 33, springs 41 and an relay 40 to battery.

closes a locki circuit for itself at its upper armature, an

43 for the rotary magn 41 and 45 as soon as relay 31 falls back after impulses. Magnet 44 therefore energizes to step the wipers 35-38 to the first set of contacts of the elected level, and at the same time breaks the locking circuit of relay If the trunk connected to this first set is busy a ground wi be present on the test contact engaged by wiper 37 so that as soon 47, springs 48, springs 39, an battery, so and the circuit of magnet 44 is again c to step the wipers onto next trunk line. As soon as an idl line is reached no ground is found bv wmer 1 switch busy 37, and relay 49, which has heretofore been short circuited energizes over a circuit from ground through springs 33, relay 49, springs 48, springs 39, and relay 40 to battery. Rela 49 being of high resistance does not al ow relay 40 to energize, but itself energizes to open the circuit of the operating magnet 32 at springs 28, prepares a locking circuit for ltsel at springs 50 and 46, which will later be su pied with ground from the switch ahea opens the circuit of relay 20, and switches the impulsing circuit from said relay 20 to the wiper 38 at springs 18 and 51. Relays 20 and 24 therefore deenergize and the operating magnets and relays of the selector rest at normal.

Assume that the idle set of contacts seized in this level is connected to the connector switch H (Fig. 2), then as soon as relay 49 energizes a circuit is closed for the line relay 52 of said connector from ground through said relay, contact 53, wiper 38, sprin 51 and 18, and over the previously trace circuit to and through the calling device C. D. of the cord circuit. Relay 52 energizes and closes a circuit for slow relay 54, which in turn energizes to place ground on the release trunk, which makes this at contact 37' and its multiples, and supplies ground to the holding circuit of relay 49 of the selector.

The calling device C..D. ma now be operated for the second digit of the called number, whereby the relay 52 operates to control the vertical magnet 55 over a circuit from ound through springs 56 an 57, sprin 58 and 59, springs 60, rela 61, and magnet 55 to battery. As soon as t e switch takes its first vertical step, springs 60 open contact and springs 62 close so that the circuit of magnet 55 and relay 61 now leads through springs 62, springs 63 and 64, and rela 61 and magnet 55. The operation of magnet 55 causes the wipers 65, 66 and 67 to be stepped to some level of the connector bank in which the desired line is located. Soon after the impulses for this digit cease, relay 61 falls back, and prepares a circuit at springs 63 and 68 for the rotary magnet 69 and slow relay 70 in multiple.

When the calling device is operated for the next or last digit of the cal ed number, relay 52 again operates to control in this case a circuit extending from ground through springs 56 and 57, springs 58 and 59, springs 62, springs 63 and 68, springs 71, relay 70 to battery, and through springs '12 and 73 to magnet 69 in multiple with said relay 7 0 to battery. Relay 7 0 remains energized during this series of impulses and for a short interval thereafter, while magnet 69 operates to step the wipers to the contacts to which the desired line is connec Assumin that the called line were bus y when the wipers test said line. then a clrcui neaaace a will be closed from ground on test contact scriber in some other exchange throu h the engaged by w per 67, through sprmegs 74 and medium of some other switch E or in- 75, springs 75 and 76, and busy r a 77 to stance. Selector E, however, would reach battery, before rela has time to f lback. a level in which the contacts are similar to Relay 77 connects usy tone to the line cirthose shown at 92, 93, 94 and 95 in Fig. 1. 7 cuit at springs 78, opens springs 71 in the Now as soon as the switch E cuts in on the operating magnet circuit, connects resistance first contact of this dead level then the 79 and battery to the line circuit to give a switch will cut throu h by the ener ation return circuit to the busy tone, and locks of relay 49 in the usuafi manner and t e dialitself to ground through springs of relay mg circuit will pass to relay 96 over wi er 7 54. Should the called line be idle, however, 38 and contact 94. Relay 96 will there ore then relay 77 will not energize and as soon energize in multiple with the line relay as relay 70 falls back, a circuit is closed for imilar to relay 52 of connector H) of the the lower winding of relay 80 from ground connector switch which has been seized by through upper sprin of relay 54, springs some selector E which has not found a dead 80 81, lower winding of zaid relay, springs 82 level. Relay 96 energizes slow relay 97 to and springs 75 and 74, wiper 67, and nn c ground through springs 98, contact relay 83 of the called partys line switch to Wipe! 7, springs 46 and 50, and relay battery. Relay 83 operates to disconnect the 49m battery over a previously traced cirrelays f th it h C f o th lin ircu1t. The selector E and other similar se- 85 cuit, and relay upon energizing over this lectors which have found a dead level will circuit connects the windings of back bridge m in out through to the contacts of that relay 84 t th t lki i it, connects dead level, until the connection is released ground through springs 85 and 74 to the pri by the operator. It will be understood that t wiper d t, d l n t i-d each switch has as many dead levels as there ground to its own upper high resistance are other SVYltCheS connectedfo the trunk winding to loek itself energized, The p- 11116 50 that If 2 ft)! instance is 'dialed then erator may now press her ringing key K t only one switch will find a connector while project alternating current out, over the rethe rest W111 all find dQfid contacts 011 that viously traced operating circuit inclu ing e ond level. an relay 52 of the connector. This alternating 488111118 w hat some subscriber such as current does not effect relay 52 but follows In ny One Of he branch exchanges dethe branch path through the tuned altern ts res to call the o erator at over the trunk ing current relay 86 which 0 erates to los line 10 and 11. his subscriber will extend a circuit for the ringing re ay 87 through a onnection through a rotary connector, se-

Springs 88, Rela, 87 now 0 grates t onlector repeater or any other well known nect the called si e of the talking current to switch to the normal contacts 100, 101 and the generator R and to the resistance 79. 4 (Fig. 1 and after testing said contacts fter the ringing is discontinued and the o determine the busy or idle condition called subscriber answers, relay 84 is operthereof, will cut through and connect a 1m scribers response, restores the listening key springs of relays 103, and disconnects the 11 K and the calling and called subscribers round at sprin 21 from the springs of ma converse. ine relay 20. 'l i e application of alternatfter conversation the operator presses ing current to the conductors 10 and 11 the release key K to allow relay 52 of the causes relay 9 to energize through current connector to fall back and close the circuit flowing in its windin in series. Relay 9 11. of the release magnet 91 of the connector by closes the circuit of t e lamp 105 to signal opening the circuit of relay 54, which relay the operator that a connection is desired, and also removes ground h g also closes circuit for the righthand wind- Clllt 0f the selector E, Whlch 111 turn 1'8 88.588. of relay 104 energizes to close The operator may tl1en remove the plug a new circuit for the lam 105 and also from the jack J in readmess for a future lo e th in 109, 'Fh closure f ll, springs 109 at this t' me completes the sim- As previously stated there are a plurality Elex operating circult of all the switches of selectors E, E, etc., connected in multiple etc., except the switch E which is, of to the trunk line 10 and 11. Now if the call course, made busy by the ground on contact had been to some other exchange than that 34 from the occupying switch. This circuit in which subscriber B is located then the may be traced to switch E, for example, selectors E, E. etc., would have been opfrom battery through the left hand winding erated to a different level and the connecof relay 104, springs 109, windings of relay tion would have been extended to a sub- 9 in multiple, conductors 10 and 11 in mulgizes to close the circuit of its associate slow relay (similar to relay 24) to ground the release trunk and contact such as 34 to make the trunk line busy to further calls.

A further result of the connection to contacts 100, 101 and 34 is the closure of the the connector switch said circuit extending winding 107 of repeating coil, contact 101, to and through a series circuit or back bridge in the occupyin connector, and back throu h contact 100, winding 108, springs 109, an relay 110 to battery. Relays 110 and 103 energize over this circuit.

Relay 103 disconnects the generator current from conductors 10 and 11 at sprin s 111 and 112, and closes a new point in t e operators side of the repeating coil at springs 113. Relay 110 closes the circuit of slow relay 114 which supplies a holding an busying ground to the release trunk contact 34 and also gized.

The operator upon perceiving the lam 105 glowing inserts the lug P in the jac J to answer the call. e insertion of the plug into the jack closes the circuit of relay 8 to open the circuit of the lamp 105 and switches the conductors 10 and 11 from the rela 9 and relay 104 to the line conductors leading to the jack J and through windings of relay 14 and the various keys to mam battery through coil 13.

that this callin an maintains relay 102 enersubscriber ed to some of the other branch exchanges which is accessible from another selector E connected to this same trunk line 10 and 11. The operator may then b means of her calling device 0. D. operate t e selectors in the same manner as ex lained in connection with the extension 0 a call to subscriber B, except that switch E will not operate and some other level of the selectors will be selected, which level is live or has trunks therein only in the exchange desired. The operation of the calling device andthe resultant operation of the switches E and H will cause no interference to the callin party as all dialing and ringing is contro ed over the simplex operating circuit as hereinbefore pointed out.

Now after conversation is completed between this call branch exchange subscriber and the 0 ed subscriber, the calling d circuit of relavs 103 and 110 d 103 and 110 and energizes in d in d switches of standard two wire t party will restore his receiver and release the switch which connected with the contacts 100, 101, and 34 in the usual manner. As soon as this switch releases, the series is opened and said relays deenergize. Relay 114 remains energized for a brief ter the deenergization of relays therefore holds relay 102 energized for a like time so that when relay 103 falls back, the alternating current 15 again connected to conductors 10 and 11 through front contacts of rela 102 and back contacts of relay 103. This a ternating current flows through the windings of relay 14 in series and causes said relay to enerize. Relay 14 upon energizing removes a short circuit from the relay 3, which relay series with the resistance 2 and battery. to close a circuit for the lamp 4 as soon as relay 14 again falls back and to revent the closure of the short circuit of itself when said relay 14 falls back. The operator will therefore remove the plug from the jack and release the extended connection in a manner before explained.

It should be understood that when a subscriber such as B, in one of the branch exchanges, desires to call another subscriber his own exchange he will use local pe which the art to cal such line and will onl connect with the trunk lines 10 and 11 w en desiring to call out of his own exchange. The switches E, E, etc., and H, H, etc.,are only for inter exchange calls.

It will therefore be seen that I have devised a very efficient and economical method of usin a single two conductor two way trunk line to extend connections in either direction over said trunk line between a main exchange and a plurality of branch exchanges. It is thought that the method of o ration of a plurality of switches over a slnglle trunk line and eliminating all but one of t e same on the first digit together with the means for making the trunk busy on calls to the main exchange and the lack of interference on reverting calls are all new and highly efiicient results together with other features pointed out.

I wish it understoodthat when a simplex circuit is referred to throughout the s ecification and claims, I refer to a circuit w ich includes the two sides of a trunk line in interval a are well known in D, parallel and which extends from one pole an im ance of a battery to a point of of con uctors,

ged across a pair through the two sides of the impedance an the two conductors in parallel and through another pair of impedances bridged across the conductors at another point and from a point of the other bridge to the opposite pole of battery.

Having fully described and ascertained the features of my invention, what I consider to be new and desire to have protected b Letters Patent, will be pointed out in t 1e appended claims.

Vhat I claim as my invention is:

1. In a telephone system, a trunk line, a plurality of automatic switches associated with said trunk line, a simplex circuit superimposed on said trunk line, and means for operating said switches simultaneously over said superimposed circuit.

2. In a telephone system, a trunk line, a plurality of automatic switches individual to said trunk line, a simplex circuit superimposed on said trunk line, and means for operating said switches simultaneously over said superim osed circuit.

3. In a te ephone system, a trunk line, means for extending connections in either direction over said trunk line, said means including a pluralit of automatic switches associated with sai trunk line, a simplex circuit superimposed on said trunk line, and means for operating a pluralit of said switches simultaneously over sai superimposed circuit.

4. In a telephone system. a trunk line, a plurality of automatic switches associated with one end of said trunk line. a simplex circuit superimposed on said trunk line, means for operating said Switches simultaneously over said superimposed circuit, means for seizing said one end of the trunk line, and means automaticall controlled by said seizure for closing said superimposed circuit.

5. In a telephone system, a trunk line, a plurality of automatic switches associated with one end of said trunk line, a simplex circuit superimposed on said trunk line, means for operating said switches simultaneously over said superimposed circuit, means for seizing said one end of the trunk line, and means automatically controlled by said seizure for closing sai superimposed circuit to make said trunk line busy to further seizure at said one end.

6. In a telephone system, a trunk line, an automatic switch associated with said trunk line, a simplex circuit su erimposed on the conductors of said trunk ine, a relay in one branch of said circuit and controlled thereover to operate said switch to extend a connection to a called subscriber, and another relay in another branch of said circuit and controlled thereover to signal the called subscriber.

7. In a telephone s stem, a main exchange, a pluralit of ranch exchanges, a trunk line exten ing from the main exchange and having branches leading to each branch exchange, an automatic switch for each branch of the trunk line, a simplex circuit superimposed on the conductors of said trunk line, branches of said circuit superimposed upon said branches of the trunk line, and means associated with each branch of the circuit and controlled thereover for operating said switches to extend connections from said trunk line.

8. In a telephone system, a main exchange, a plurality of branch exchanges, a trunk line exten ing from the main exchange and having branches leading to each branch exchange, an automatic switch for each branch of the trunk line, a simplex circuit superimposed on the conductors of said trunk line, branches of said circuit superimposed upon said branches of the trunk line, and means associated with each branch of the circuit and controlled thereover for operating said switches to extend connections from said trunk line to said branch exchanges.

9. In a telephone system, a. main exchange, a pluralit of branch exchanges, a trunk line exten ing from the main exchange and having branches leading to each branch exchange, an automatic switch for each branch of the trunk line, a. simplex circuit superimposed on the conductors of said trunk line, branches of said circuit superimposed upon said branches of the trunk line, and means associated with each branch of the circuit and controlled thereover for simultaneously operating said switches to extend connections from said trunk line.

10. In a telephone system, a two way trunk line having movable terminals for extending connections therefrom and fixed terminals for extending connections thereto, an automatic switch for controlling said movable terminals, a simplex circuit including said trunk line for operating said switch, means for establishin a connection with said fixed terminals 5111C? for applying ringing current thereto, and means controlled by the application of said ringing current for operating a signal at the opposite end of said trunk line and for automatically closing said operating circuit.

11. In a telephone system, a trunk line, comprising a pair of conductors, a. plurality of automatic switches individual to said trunk line, a line relay for each switch, a circuit including the two conductors of said trunk line in parallel for energizing said relays, and means for controlling said circuit to operate said switches to extend connections from said trunk line.

12. In a telephone system, a trunk line comprising a pair of conductors, a plurality of automatic switches associated with said trunk line, a line relay for each switch, a circuit for each relay including the two conductors of said trunk line in parallel, means for controlling said circuit to operate said switches to extend connections from said trunk line to called subscribers lines, and

another relay included in said circuit with each line relay for signalling the called subscribers.

13. In a telephone system, an operators position, a two-way trunk line leading from said position and terminating at the opposite end in a plurality of automatic sw tches, a line relay for each switch, a c rcuit for said relays including the conductors of said trunk line in parallel, and means at the 0perators position for controlling said circuit to operate said line relays simultaneously to extend connections from the trunk line.

14. In a telephone system, an o erators position, a two way trunk line leading from said position and terminatmg at the op 0- site end in a plurality of automatic switc es and a plurality of fixed terminals, a line relay for each switch, a circuit for said relays including the conductors of said trunk line in parallel, means at the operators position for controlling said circuit to operate said line relays simultaneously to extend connections from the trunk line, means for seizing any of said fixed terminals, and means automaticall controlled by such seizure for closing sai circuit.

15. In a tele hone system, a two way trunk line exten in from an operators position to branch exc anges, means for establishing a connection with the branch exchan e end of said trunk line from one of said ranch exchanges and for signalling the operator at said position, and a switc individual to said trunk line controlled thereover by the operator for establishing a connection from said trunk line to another of said branch exchanges without disturbing the connection from the first branch exchange.

16. In a telephone system, a line, several automatic switches having access to said line at the same end thereof, a simplex circuit individual to said line, and means involving the use of said sim lex circuit for making said line bus to al other switches when seized b one 0; said other switches.

17. In a te ephone system, a line accessible to several automatic switches, a pluralit of other switches individual to said trun line to extend connections therefrom, a simplex circuit superimposed on the conductors of said trunk line for operating said other switches, said simplex circuit automatically closed when the line is seized by anyone of said first switches to control means for making said line busy to all of the rest of said first automatic switches.

18. In a telephone system, a trunk line, an automatic switch therefor, a simplex circuit superimposed on the conductors thereof, a relay included in said simplex circuit to operate said switch to extend a connection to 0. called subscriber, and another relay included in said simplex circuit and energized thereover to signal the called subscriber.

19. In a telephone system, a trunk line, an automatic switch therefor, a simplex circuit superimposed on the conductors thereof, a. relay included in said sim lex circuit to operate said switch to exten a connection to a called subscriber, and another relay included in said simplex circuit and energized thereover to signal the called subscriber, said first relay controlled by direct current and said other relay controlled by alternating current.

20. In a telephone system, a twoway trunk line, a pluraht of switches individual to one end thereo for extending connections therefrom, an operator at the other end thereof, means for seizin the one end of said trunk when a connection is desired, and means controlled by the operator for operating said switches to extend a connection excluding all except one of said switches and the end of the trunk leading to the operator.

21. In a telephone system, a trunk line leading from an operators position to a plurality of branch exchanges, automatic switches for said trunk in each exchange, means for seizing said trunk line at any branch exchange and for signaling the operator, and means controlled by the operator for operating an automatic switch in any other of said branch exchanges over said trunk line to extend a connection to a called party in that branch exchange over said trun line without interfering with the connection to the trunk line from the first branch exchange.

22. In a telephone system, a trunk line havin a plurality of branches at one end, each ranch terminating in an automatic switch, means for transmittin impulses over said trunk line to o erate said switches simultaneously, and loca trunk lines terminated in different positions in' said switches so that the local trunk connected with depends entirely on the particular digit transmitted.

23. In a telephone system, a trunk line havin a plura ity of branches at one end, each ranch terminatin in an automatic switch, a group of trunk ines terminated in a particular position in one of said switches, ot er groups of trunks terminated in the other switches, respectively, each group terminating in a different position in the associated switch, and means for operating all said switches simultaneously to the same position to select a particular group of trunks by means of one of said switches, or for operating all of said switches simultaneously to a different position to select a different group of trunks by means of another of said switches.

24. In a tele hone system, a trunk line having a plura ity of branches at one end,

messes each branch terminating in an automatic switch,-a live position and a plurahty of dead positions in each switch, the dead positions in each switch corresponding to the live positions in the other switches, a local mg located in a dlfl'erent exchange, a comline terminating at the live position on each switch, and means for operating and switches simultaneously to any (posltion to connect the trunk line with any esired one of said local lines. f v

25. In a tale hone system, a trunk hne havin a plura ity of branches at one end,

each ranch terminating in an automatic switch, a live level and a plurality of dead levels in each switch, the dead levels in each switch being the levels which correspond to the live le els in the other switches, a local line terminating in the live level at each switch, and means for operatin said switches simultaneously to any level connect the trunk line with any desired one of said local lines.

26. In a telephone system, a trunk 11116 having two branches at one end, each branch terminating in an automatic switch, a local line terminating in a certain leuel of one of said switches, a second local lme termnating in a different level of the other of said switches, and means for operating both switches simultaneously to either level to connect the trunk line with either local line by means of the associated switch.

27. In a telephone system, a trunk line having two branches at one and, each branch terminating in an automatic switch, a local line terminating in a certain level of one of said switches, a second local line terminating in a diiierent level of the other of said switches, means for operating both switches simultaneously to either level to connect the trunk line with either local lineb means of the associated switch, and a hol circuit for each switch terminat' in e level which corres nds to the level of the other switch in which the local line terminates.

28, In a telephone system, a trunk line terminating at one end in an automatic :switch,-means including a second switch for connecting with said trunk line at the same end, means for automatically rejecting ringing current over the trunk ine when the connection is established, and means at the other end of said trunk line-responsive to ringing current for completing a control circuit for said'first switc 29.- In a telephone system, a trunk line terminating at one end in an automatic switch, means including a second switch for connecting with said trunk line at the same end, means res onsive to the establishment of said connectlon for closing a circuit over said trunk line including the two sides there-- of in series, and means at the other end of said trunk line res nsive to the closure of said series circuit or closing a control circuitfor said first switch includin -the two sides of said trunk line in paralle 80. In a telephone system a trunk line connected in multiple to a plurality of incoming automatic switches, each switch bemonoperating circuit for said switches including a con uctorof said trunk line, outgoing automatic switches in each exchange or connecting with said trunk line, and" means for closing said operating circuit when the trunk line is connected. wlth by an outgoing switch in anyone of said exchanges.

81. In a telephone system, a trunk line connected in multiple to a plurality of incoming automatic switches, each switch being located in a difi'erent exchange, a common operating circuit for said switches including a conductor of said trunk line, outgoing automatic switches in each-exchange for connecting with said trunk line means for closing sald operating circuit when the trunk line is connected with by an outgoin switch in an one of said exchan and means in the incoming switches in t e other exchanges responsive to the closure of said circuit for making said trunk line busy to the outgoing switches in said other exchanges.

'32. In a telephone system, a main exterminates, means including another automatic switch controlled by a. calling sub scriber in one of said branch exchanges for connecting with said trunk line, and means at said switchboard for transmitting impulses over said trunk line to. operate the toll switch at the proper branch exchange to extend the connection to the called line.

33. In a telephone system, a trunk line terminating at one end at a manual switchboard a cell signal for saidctrunk, means including an automatic switch controlled by a calli subscriber for connecting with said trunk hne at the other end, means responsive to the completion of the connection for auto matically pro ecting ringing current over said trunk ine to cause the operation of said cell signal, and means for automatically and permanently opening the ringing circuit beore the operator, answers the call.

34. In a telephone system, a trunk line I sociated with said connecting sai t eration of said disconnect sign by the calling for automatically encrgizm trunk line at; the other end, operatorsequipment for connecting said trunk linev with a called. line, a disconnect signal assponsive to the re acement of the receiver subscriber for automatically rojecting ringing current over said trunk line ti): cause the operation of said disconnect s1 a l t i. In a telephone system, a trunk line terminating at one end at a manual switchboaniiua call signal for said trunk means inclu g an automatic switch controlled by a calling subscriber for connectingwith said trunk line at the other end, means responsive to the completion of the connection for auto matically rojecting ringing current over said trunk ine to cause the o ration of said call signal, a ring cut-ofi' re ay, and means said relay before the operator answens t e call.

37. In-a telephone system, a. trunkline 'terminatin at one end at a manual switchboard, a signal for said trunk, means including an automatic switch controlled by a 1 calling subscriber for connecting with said trunk line at the other end, means responsive uipment, and means relmes exten a si to the iiimpletigtgfg the connection for automa ica y pro] ,rmgm current over sa d trunlr hne to cause tin e-operation of and call I, and means also naive to thettlalom etipn of tlgzionnegigon ital; stopping e ope on ere eoerator answers :fie call. P

{38 a telephone exchange stem, an originating pfice, an on lying 0 re, trunk hnes extending between said oifices, an automatic switch in said first oilice for selecting one of said trunk lines, individual to said trunk line at the nutgoin end thereof, a signalassociated with sai trunk hne the incoming and theme means madaeifective by the seizure of sai trunk line by saiiswitch to 0 rate said nsive means, and means un er the controdi of said responsive means for operating sax s1 d9. a telephone exchange system, an originating pfiice, an outlying oflice, trunk said oflices,aoord circuit at an second oflice for; connection with said trunk lines, an automatic switch in said first ofiioe for selectingone of said trunk lines, nsive means associated with saidtrunk at the outgoing end thereof, gnal associated with said trunk line at the incoming end.thereof, a second al in said eordcircuit, and means made e ective by the seizure of said trunk line by said switch to operate said responsive means to thereby operate said first signal and effective upon release of said trunk line to operate said seconds al.

Signed by me at.Ghiea Cook County, Illinois, this 13th da of une, 191s.

BER ARD D. WILLIS.

nsive means Q of said call si connecting sai t trunk line at the other end, operatorsequipment for connecting sald trunk hne. th at calledline, .sociated with said a. disconnect signal assponsive to the rep acement of the receiver by the subscriber for automatically rejecting ringing current over said t-run line to cause the operation of said dlsconnect signal: w

36. In a telephone system, a trunk 1me terminating at one end at a manual switchboardi; cell signal for and trunk, means inclu g an automatic switch controlled by a calling subscriber for connectmgwlth sald trunk line at the other end, means responsive to the completion of the connection for auto matically rejecting ringing current over said trunk ine to cause the tion of said call signal, a ring cut-ofi' re ay, and means for automatically energizin said relay before the operator answers e call.

37. In a a telephone system, a trunkline terminaticifilat one end at a manual swltchboard, a signal for said trunk, means 1ncluding an automatic switch controlled by a calling subscriber for connecting with said trunk line at the other end, means responsive uipment, and means reexten to the inmpletggntggg the connection for automa lca y pro ,rmgm current over said trunlr line to cause th e'operation of said call an al, and means also responsive to the comp etion of the connection for stopping the operation before the operator answers t e call. a

8 8. In a telephone exchange gstem, an originating oflice, an outlying o co, trunk lines extending between said oflices, an automatic switch 1n said first oflice for selecting one of said v individual to said trunk e at the nutgoin end thereof, a signal associated with sai trunk line at. the incoming end thereof means madenefiective by the seizure of sai trunk line by said. switch to o crate said onsive means, and means an or the contro of said TGSPODSIVB means for operating said si a1.

t9 a tegphone extclhan1 ge stemtugn ori matmgo ce,anou ymgo ce,

g between said oflices, a cord circuit at 'sai second oflice for; connection with said trunk lines, an automatic switch in said first oflice for selectingone of said trunk lines, responsive means associated with and trunk at the outgoing end thereof, a signal associated with said trunk line at the incoming end .thereof, a second si al in said cord circuit, and means made e cotive by the seizure of said trunk line by said switch to operate said responsive means to thereby operate said firsrtlslifinal and efl'ective upon release of said t bus to operate said second signal.

Signed by me at.Chic'a Illinois, this 13th do. of true, 1918.

BER ARD D. WILLIS.

blscLAline-ea't- D. Willia, Oak Park, 11L S monr'ro e l O l 7 1925. Disclaimer m a W y mesne assignments, AutonwticFkctricI m, an s. by t e assignee areintl di ll wmg' alt c1 00 w 83. In a teie hone i mt switchboard, a sign for said t aims 88, 36, and 87 in said specification which a trunk line terminating at one end at a manual runk, means incl ding tome trolled by a calling ubscrlber for connectin u an m hm swmh eon means responsive to the completion of ringing current over said trunk line means for antomaticall and operator answers the ca f86. In a telephone switchboard, a'call signa operator answers the call.

37. In aftele for said trunlt, means inclu to cause the operation of said c pemnanently opemn'g the ringing circuit before the g with said trunk lineat the other-end, the connection for automaticall projectin signal, an

tem, a trunk line terminating at one, end at a manual for said trun means includ' trolled by a calling subscriber for c'imniiritmg mg m automatlc'mtch con means responsive to the completion of the connection f rmgmg current over said trunk line to cause th or autumnal] ring cut-oil relay, and means for automatically with said tnmk line at the other end,

e of said energiz ng said relay before the dmg an automatic switch con- 3 Stem a s v i whboard, a i trunk e rminatin at; one end at a manual trolled by a callingsu w for connect mgwith saidtrunklineatthe otherend.

means responsive to the completion of theoonnection for automaticall' mrmgmgBans aIscurl-calm; over szziodthtrunk linetto canstmla1 the operationf of said call slgnal an onslve ecomp e mu 0 0 connection or op ranon before the op rator answers the call. stoppmg the mguig y rejecting call signal, a

I5 Cook County,

DISCLAIMER}.

1,532 849.-Bemard D. Willis, Oak Park, III. -S momma 'lnmomu SYSTEM. iatent dated April 7, 1925. Disclaimer filed anuary 3, 1928, by the assignee by mesne assignments, Automatic Electric Inc.

Hereby enters a disclaimer to claims 33, 36, and 37 in said specification which are in the following words, to wit:

33. In a telephone stem, a trunk line terminating at one end at a manual switchboard, a call signzl for said trunk, means including an automatic switch controlled by a calling subscriber for connecting with said trunk line at the other end. means responsive to the completion of the connection for automatically projecting ringing current over said trunk line to cause the operation of said call signal, and means for automaticall and permanently opening the ringing circuit before the operator answers the ca 1.

36. In a telephone system, a trunk line terminating at one end at a manual switchboard, a call signal for said trunk, means including an automatic switch controlled by a calling subscriber for connecting with said tnmk line at the other end, means responsive to the completion of the connection for automatically projecting ringing current over said trunk line to cause the operation of said call signal, a ring cut-ofl' relay, and means for automatically energizing said relay before the operator answers the call.

37. In a telephone system, a trunk line terminating at one end at a manual switchboard, a call signa for said trun k, means including an automatic switch controlled by a calling subscriber for connecting with said trunk line at the other end, means responsive to the completion of the connection for automaticallliy projecting ringing current over said trunk line to cause the operation of said ca signal, an means also responsive to the completion of the connectionfor stopping the ringin operation before the operator answers the call.

[0W Gazette January 17', 1.9%.] 

